Portable computing devices such as, e.g., personal digital assistants, display-enhanced cellular telephones, portable electronic document readers, and interactive electronic guidebooks are typically produced with displays that are limited in visual area because the portable computing devices are preferably designed to be conveniently carried in the human hand. This is particularly true where the display is integrated with the body of the portable electronic device.
Accordingly, it would be desirable to provide a display that can be stored in a small space, but can be subsequently opened into a form that is much wider than the device to which it is attached. Preferably, an opened display for a portable device should be rigid enough that the user does not have to provide separate support for the display or set the portable device on a flat supporting surface. It would be additionally advantageous for the display to be easily opened with one hand since the other hand is usually used to support the portable computing device.
There has been prior work on displays that can be expanded to a greater viewing area. For example, FIG. 1 shows a known four-segment hinged display device 100 as described in U.S. Pat. No. 6,088,220 titled Pocket Computer with Full-Size Keyboard. Each half of the display 100, as shown, has been folded out along a respective pair of horizontal hinge arrangements 120-180. Hinged displays of this kind require repetitive manual actions to open or close the display, and generally involve flex cabling across each hinge arrangement which introduces additional potential failure points to the display. Further, this type of display arrangement multiplies the number of segment boundaries which results in visible seams in the display unless additional steps are taken.
Published U.S. patent application Ser. No. 10/719,300, titled Collapsible Display Device and Methods for Using the Same, discloses a number of fold-up display geometries that use non-right-angle folds, twists and pivots to reduce the number of manual actions needed to open the display. For example, FIG. 2 shows a display 200 which consists of a number of display segments 220 that open around a pivot 240. Also disclosed are fold-up displays similar to folding fans, twist-up displays using spring-like exterior rings, pop-up displays that apply “pop-up book” techniques, and umbrella displays that apply a hub-spoke umbrella action.
Roll-up displays utilizing flexible display materials have been proposed such as, e.g., the roll-up display 300 shown in FIG. 3 and disclosed in U.S. Pat. No. 6,498,597 titled Continuously Displayable Scroll-Type Display. The roll-up display device 300 utilizes a scroll-like flexible display medium 320 which is stored in a cylindrical magazine 340. A practical issue arises from using a flexible display material which is preferably viewed flat, and which is also sometimes fragile.
One approach is to utilize an accordion-like support structure similar to the one disclosed in U.S. patent application Ser. No. 10/012,558 titled Mobile Terminal Device, Content Distribution System, Content Distribution Method, and Program for Executing Method Thereof. With reference to FIG. 4, the roll-up display device 400 includes an accordion-like supporting structure 420 for supporting the flexible display material 440. Other roll-up displays use a “bamboo scroll” type of supporting structure which provides lateral support, but does not provide longitudinal support. It should be noted that, while the roll-up configuration has the advantage of expanding for use and collapsing to a smaller area for storage, the area to which it collapses is still limited in its degrees of freedom by its constant width, as is the area to which it expands. In other words, although the display area can be changed in its length dimension, its width dimension is generally fixed.
Accordingly, it would be advantageous to introduce display configurations that overcome certain disadvantages of existing technologies.